Multicenter and multimodal imaging study reveals rare fundus lesions in patients after SARS-CoV-2 infection

To define the characteristics of fundus manifestations in patients after SARS-CoV-2 infection with multimodal imaging techniques. This is a retrospective multicenter and multimodal imaging study including 90 patients. All patients with a visual complaint occurring immediately after SARS-CoV-2 infection were referred to six clinics between December 2022 and February 2023. Demographic information and the temporal relationship between SARS-CoV-2 infection and visual symptoms were documented. The characteristics of the fundus lesions were evaluated using multimodal imaging. Ninety patients from six hospitals were included in this study, including 24 males (26.67%) and 66 (73.33%) females. Seventy-eight patients (86.66%) (146 eyes) were diagnosed with Acute Macular Neuroretinopathy (AMN). The AMN patients were primarily young women (67.95%). Sixty-eight patients (87.18%) had AMN in both eyes. Thirty-eight eyes (24.36%) included Purtscher or Purtscher-like lesions. optical coherence tomography and infrared retinal photographs can show AMN lesions well. Eleven cases were diagnosed with simple Purtscher or Purtscher-like retinopathy (2 cases, 2.22%), Vogt‒Koyanagi‒Harada (VKH) syndrome or VKH-like uveitis (3 cases, 3.33%), multiple evanescent white-dot syndrome (MEWDS) (2 cases, 2.22%), and rhino-orbital-cerebral mucormycosis (ROCM) (5 cases, 5.56%). After SARS-CoV-2 infection, diversified fundus lesions were evident in patients with visual complaints. In this report, AMN was the dominant manifestation, followed by Purtscher or Purtscher-like retinopathy, MEWDS, VKH-like uveitis, and ROCM.

the initial or later stage 9 .However, few studies have systematically described the manifestations of the posterior segment of the eye by multimodal imaging study 10 .
Due to the lockdown policy was suddenly lifted, there was a surge in the number of Omicron infections in Chinese people from late December 2022 to late January 2023 in China 11 .Based on the large number of SARS-CoV-2 infected patients, it was possible for us to observe a series of patients with rare fundus Lesions after SARS-CoV-2 infection.These rare fundus lesions with a large increase over the same period of the previous year may be related to SARS-CoV-2 infection.Because these lesions are rare and often lead to misdiagnosis, reasonable examination methods can help us quickly identify lesions and diagnose them.
In the present case series, multimodality imaging was used to describe retinal and/or choroidal conditions that could be associated with SARS-CoV-2 infections.We outlined the features of retinal and choroidal manifestations following SARS-CoV-2 infections and clarified the best diagnostic methods to improve our understanding of their pathogenesis and diagnosis.

Participants
This was a cross-sectional multicenter and multimodal imaging study.From December 2022 to February 2023, 90 patients were identified with retinal and/or choroidal conditions associated with COVID-19 infection in six clinics, including the First Affiliated Hospital of Zhengzhou University and/or Zhengzhou University People's Hospital and/or The Second People's Hospital of Zhengzhou and/or Luoyang Central Hospital Affiliated to Zhengzhou University and/or Nanyang Eye Hospital, Nanyang and/or The First Affiliated Hospital of Nanyang Medical College.The incidence of these diseases in the same period of the previous year was collected from the outpatient information databases of those hospitals.
All patients tested positive by real-time reverse transcription-polymerase chain reaction (RT-PCR) and/ or antigen detection for SARS-CoV-2 from pharyngeal or nasopharyngeal swabs during the active phase of SARS-CoV-2 infection and eye symptoms occurred whitin one month after SARS-CoV-2 infection.Patients who were not infected with SARS-CoV-2 and whose ocular symptoms occurred more than one month after SARS-CoV-2 infection were excluded.
This study was approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University [2023-KY-0637].Based on the Declaration of Helsinki, we collected demographic information, SARS-CoV-2 infection symptoms, chief complaints and other clinical examination results after informed consent was signed by the patients or their guardians.The clinical examination results included slit-lamp examination and indirect ophthalmoscopy results, best corrected visual acuity (BCVA), spherical equivalent (SE), fundus photo images, visual field analysis (VF), infrared retinal photographs (IR), optical coherence tomography (OCT), optical coherence tomography angiography (OCTA), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), multifocal electrophysiology (mf ERG), fundus autofluorescence (FAF) and adaptive optics (AO).All patients were diagnosed and recorded by 2 doctors individually.In cases of disagreement, the senior ophthalmologist made the final decision.

Method of eye examination
All outpatients were examined by slit-lamp and ophthalmoscopy.BCVA and SE were tested by optometrists.Fundus photos and FAF were taken using an ultrawide field fundus camera (Daytona P200T, Optomap, UK) and fundus camera (CLARUS 500 v1.1, Carl Zeiss Co. Ltd., Germany).
Skilled ophthalmologists performed swept source OCT (SS-OCT) (VG200 or VG100, SVision, China) or spectral domain OCT (SD-OCT) (Spectralis OCT, Heidelberg Engineering GmbH, Germany), which included stars in 16 or 32 lines and multiline scanning with a scan line length of 10-16 mm.SS-OCTA scanning was performed with a scan square of 6 mm × 6 mm or 12 mm × 12 mm.The depth of the scanning was 3-6 mm.The scanning laser wavelength was 1050 nm or 870 nm.IR images were taken by a 40° × 40° confocal scanning superluminescent (diode) ophthalmoscope (cSSO) with a wavelength of 820 nm or confocal scanning laser ophthalmoscope (cSLO) with a wavelength of 810 nm.
FFA and ICGA (Spectralis HRA, Heidelberg Engineering GmbH, Germany) were performed to observe vascular lesions.AO (rtx1, Imagine Eyes, Orsay, France) was performed to clarify the status of the optic cone optic rod cells.

Statistical analysis
SPSS statistics 26.0 software (IBM Corp.; USA) were used to analyze the data.Categorical data are described using frequencies and percentages.The Kolmogorov-Smirnov test was performed to verify whether all the data sets were distributed normally.Continuous variables with a normal distribution are presented as the mean ± standard deviation (SD), and a t test was used for comparisons.Nonnormal variables are reported as medians (interquartile ranges).A P value less than or equal to 0.05 was considered statistically significant.

COVID-19 infection, vaccination history and demographics of patients
Ninety patients were included in this study, including 24 males (26.67%) and 66 (73.33%) females.Their age was 31 ± 15 years old with a range of 10-85 years (Table 1).
All patients had a history of COVID-19 infection.Visual symptoms occurred 0-30 days after the onset of fever, dry cough, malaise, etc.The mean interval between COVID-19 infection and visual symptom onset was median 2 days, IQR [2, 3].Five patients had diabetes, six patients had kidney disease, four patients had hypertension.
However, in December 2021 to February 2022 year, there were only one Purtscher retinopathy patient with chest trauma, one ROCM patient and two AMN patients.Although there are as many as 21 patients first diagnosed as VKH, their clinical symptoms are different from those after SARS-CoV-2 infection.The number of MEWDS patient cannot obtain because MEWDS does not have an ICD diagnostic code.

Acute macular neuroretinopathy (AMN) and Purtscher or Purtscher-like retinopathy
A total of 78 patients (146 eyes) were diagnosed with AMN, including 22 males (28.21%) and 56 (71.79%) females.Their age was 29 ± 11 years old with a range of 10 to 64 years old.The majority of patients were young women (67.95%).There was no statistically significant difference in age between the sexes (t = − 0.22, P = 0.830).Their complaints were "black shadows or dark spots in front of the eyes or visual field defects" (38 cases, 48.72%) and "blurred vision."(40 cases, 51.28%).
Ten patients (12.82%) had visual problems in one eye.Sixty-eight patients (87.18%) had visual problems in both eyes.The BCVA of the 146 diseased eyes was median 0.13, IQR [0.00-0.36]logMAR with a range of 0.00 to 2.00 Log MAR.In a total of 146 eyes with AMN, the BCVAs at presentation were generally well documented to be 0.30 LogMAR or better (96 eyes, 65.75%).1.00 LogMAR or worse in 18 eyes (12.33%).
At the initial visit, nineteen of the seventy-eight cases (38 of 146 eyes; 24.36% of cases, 26.03% of eyes) presented with either cotton-wool spots or Purtscher-like retinopathy.Ten of these patients (52.63%) had kidney disease or hypertension.
Fundus photos were taken in 57 of 146 eyes.The lesions showed wedge-shaped petal-shaped, oval slightly dark areas in 16 eyes (28.07%) (Fig. 2 A1,A2).The contrast sensitivity of the fundus photo was not as good as that of IR and OCT (Fig. 2B1,B2,B3,B4,C1,C2, Fig. 3C).Four eyes underwent AO and showed small patches of cone rod cell loss in the area corresponding to the lesions (Fig. 2D1,D2 yellow boxes).Ten eyes underwent mf ERG and all showed one to several abnormal findings, including diminished amplitudes and diminished implicit time (Fig. 2E1,E2,E3,E4,E5,E6, Fig. 3B1,B2).Thirty-six eyes with AMN experienced one to several paracentral scotomas by Amsler grid, VF or micro-VF testing.The mf ERG and VF specialty corresponded closely to the shape and location of the clinical lesion (Fig. 3A,B1).The shape of VF abnormalities was wedge-shaped, boot-shaped, and round-shaped (Fig. 2F1,F2).The en face OCT exhibits the same hypo reflectivity as the OCT B-scan (Fig. 3D).

VKH-like uveitis and multiple evanescent white-dot syndrome (MEWDS)
A 49-year-old female patient presented with complaints of visual distortion in both eyes, without accompanying headache or tinnitus (Fig. 4A,B,C).Initial BCVAs were 0.52 Log MAR for the right eye and 1.3 Log MAR for the  treatment, her BCVAs improved to 0.00 LogMAR in both eyes.Subsequent FFA and OCT imaging showed a reduction and eventual resolution of neurosensory retinal detachment over time (Fig. 4G1,G2).The patient underwent a one-month course of systemic corticosteroid treatment and did not experience any relapse over the following six months.Following SARS-CoV-2 infection, these two patients developed blurred vision and exhibited inflammation in both the anterior chamber and the vitreous body.Their symptoms are consistent with the typical manifestations of Vogt-Koyanagi-Harada (VKH) disease, characterized by pan-uveitis and multifocal serous retinal detachment, specifically granulomatous uveitis.Notably, this included mutton-fat KPs, a hallmark of VKH disease.However, unlike typical VKH cases, they did not show systemic symptoms such as tinnitus and skin changes.However, they responded well to corticosteroid treatment without any relapse.
A 21-year-old male patient was diagnosed with MEWDS and complained of "blurred vision on the left eye" five days after a fever caused by SARS-CoV-2.The BCVAs were 0.00 and 0.10 LogMAR in his right and left eyes.Some yellow-white punctate lesions were faintly seen on fundus photography (Fig. 5A1,A2), OCT showed that there were structural abnormalities in the outer retina (Fig. 5C1,C2).The mf ERG showed that the visual sensitivity of the patient's left eye was reduced (Fig. 5D1,D2).There were some highly fluorescent lesions on the FAF (Fig. 5B1,B2) and scattered high fluorescence spots on FFA (Fig. 5E).However, the patient did not undergo ICGA due to drug allergies.We suggested that the patient should return to the clinic two weeks later, but he did not return.Then, we performed a telephone follow-up and were informed that his symptoms had been eliminated.Another 37-year-old female had similar symptoms.

Rhino-orbital-cerebral mucormycosis (ROCM)
A 49 year-old male patient with SARS-CoV-2-related pneumonia had recurrent fever for 20 days and underwent "intracranial hematoma drainage" because of "diabetic ketoacidosis and cerebral hemorrhage."Then, he developed swelling on the right side of the face 3 days later.Sooner afterward, he suddenly lost vision in his right eye.This patient had a history of high blood pressure and diabetes but did not take medications regularly.Due to fever and infection, his vital signs were unstable, and his right eye was not treated (Fig. 6B).Pale retinal and "cherry red spot" suggested central retinal artery occlusion (CRAO).Fungal cultures of nasal tissue in patients showed wide septum hyphae, which was characteristic of Mucormyces.This confirmed that he had ROCM.The patient's right eyeball was fixed in the upper right position and could only be slightly moved up and down instead of left and right (Fig. 6A).Unfortunately, the optic disc of the right eye was pale (Fig. 6B1).Interestingly, we observed cotton-wool spots around the optic disc of the left eye (Fig. 6B2.B3).OCT showed retinal-choroidal atrophy and   A, B, C, D, E) and a 43 year-old female (F, G).Initially, the vitreous was opaque in the 49-year-old female (A).FFA (B) and ICGA (C) showed optic disc leakage and fluorescence accumulation in the advanced macula.After 3 days of treatment, the vitreous opacity was reduced (D), and neurosensory retinal detachment decreased (E).In the 43 year-old female, FFA (F) initially showed optic disc leakage.After treatment, neurosensory retinal detachment decreased, and choroidal thickness was reduced over time (G).interlaminar edema in his right eye (Fig. 6C1).The cotton-wool patch showed thickening of the neuroepithelium (Fig. 6C2,C3 yellow arrow head).The patient's magnetic resonance imaging (MRI) showed abnormal signals in the right orbital tip (Fig. 6D1,D2,D3).
Another 49-year-old female patient was also diagnosed with ROCM.She also had diabetic ketoacidosis, which suggested poor glycemic control.Similarly, she lost her vision in her right eye.Fundus photographs showed cotton-wool spots and hemorrhages on her left eye as well (Fig. 6E1,E2).OCT images showed the acute phase of arterial occlusion with extensive retinal edema (Fig. 6F1) and Purtscher-like retinopathy (Fig. 6F2 yellow arrow head).Blood tests showed that her white blood cells were 13.68 (reference 3.5-9.5)10^9/L, neutrophil percentage was 83.5% (reference 40-75%), DD-dimer was as high as 10.79 (reference 0-0.3) mg/L (DDU), fibrinogen degradation products (FDP) were as high as 10.79 (reference 0-5) mg/L, and C-reactive protein (CRP) and procalcitonin (PCT) and interleukin 6 (IL-6) were more than 5 times the normal value.
Both patients did not receive ocular treatment because their vision was no light perception (NLP).In addition, three other female patients aged 77, 81, and 85 years who had ROCM and diabetes underwent eye removal.

Discussion
There have been more than 757 million confirmed cases and 6.8 million deaths being reported worldwide since the outbreak of COVID-19 in November 2019 13 .By targeting the ACE2 receptor in human endothelial cells, SARS-CoV-2 attacks host cells through the transmembrane spike protein (S protein).Therefore, tissues with ACE2 receptors are susceptible to SARS-CoV-2 infection 14 .ACE2 is widely expressed in endothelial cells of the lung, blood vessels, heart, kidney, small intestine and other tissues and organs, with low expression in the liver and nose.These organs are vulnerable to damage following SARS-CoV-2 infection 15,16 .Moreover, ACE2 is a major converting enzyme in the vascular protective axis of the renin-angiotensin system in the retina, and its downregulation may lead to retinal ischemia, which is related to microangiopathy, retinitis, and retinal degeneration [16][17][18] .
The meta-analysis conducted by Sen et al 3 in 2021 revealed that conjunctivitis is the principal ocular manifestation following SARS-CoV-2 infection, with previous research largely focusing on individual case reports.In contrast, our research expands the scope by presenting a substantial series of cases from six medical centers, utilizing multimodal imaging to document the experiences of 90 patients.This approach provides robust evidence of ocular involvement after SARS-CoV-2 infection.Our findings underscore that in the real world, AMN is a significant and closely associated retinal lesion with after SARS-CoV-2 infection, highlighting its prevalence and clinical importance in affected patients.
Previous literature has reported retinal and choroidal manifestations that may be associated with SARS-CoV-2, as shown in Table 2. Based on the pathological mechanism, we classify these manifestations as noninfectious or infectious.Noninfectious manifestations may be related to ischemia or inflammation.RVO and RAO are common diseases in ophthalmology, and patients often have underlying diseases such as diabetes and hypertension 19,20 .Therefore, these diseases were not included in our case series as fundus lesions related to SARS-CoV-2.However, rare eye diseases such as AMN and ROCM have increased in incidence alongside the rise in SARS-CoV-2 infection rates 21,22 .

Acute macular neuroretinopathy and Purtscher or Purtscher-like retinopathy
We observed this case series with SARS-CoV-2-related retinal and choroidal manifestations.Typically, the patient was a young woman who developed visual impairment two days following the onset of infection symptoms.As  E, F). White arrowhead showed the cherry erythema in B1, while yellow arrowhead showed the cottonwool spots in B3 where the nerve fiber layer was swelling (C3).F1 showed the acute phase of arterial occlusion with extensive retinal edema.the standard, with the relationship of cause, trigger and disease, our results suggested a close relationship between the emergence of AMN or Purtscher or Purtscher-like retinopathy and SARS-CoV-2 infection.
AMN is a relatively rare disorder involving transient or permanent central or paracentral scotomas 39,40 .It is characterized by dark, reddish-brown macular lesions and corresponds precisely to visual field abnormalities 41 .AMN has been reported to occur in several different clinical settings.3][44][45][46][47] .Since the syndrome was initially characterized by Bos and Deutmann 49 in 1975, the pathophysiology of AMN has been the subject of intense discussion, especially in light of the disorder's diverse causes.
Acute retinal lesions are characterized by faint retinal translucency on bio microscopy and hyperreflectivity in the outer plexiform and outer nuclear layers on OCT.FFA and ICGA do not reveal any retinal or choroidal vascular leakage, perfusion deficits or transmission defects.mfERG testing shows reduced amplitudes within the scotomatous areas 50 .Evolution of macular lesions is characterized by resolution within several days of the initial retinal translucency and hyperreflectivity, followed by the development of reddish-brown lesions that appear dark on IR and show thinning of the outer nuclear layer and attenuation or loss of the ellipsoid and interdigitation zones on OCT.Compared to FFA, ICGA and FAF, OCT and IR images display the lesions of AMN more effectively.The cSSO fundus photography used in this study is a laser with a wavelength of 820 nm; it is also an IR imaging approach in essence.Due to the destruction of the elliptical zone, the laser is absorbed by the deeper and stronger retinal epithelium, demonstrating the essence of shadow and OCT is optical coherence imaging, and the areas with mixed or dense tissue structure will show high reflection 51 .From the perspective of imaging alone, the morphology of hyper reflex in the early stage of the onset of AMN was consistent with that of the fiber of the cone and rod cells, which indicates the affected site (Fig. 1A1,A2) 41,48 .At present, the generation of AMN is mainly dominated by two theories: the inflammation-related immune theory and the vascular-related ischemia and hypoxia theory 50,52 .This needs to be discussed in combination with vascular parameters, and our research team will explore in future research.

VKH-like uveitis and multiple evanescent white-dot syndrome (MEWDS)
VKH disease is an immune-mediated disorder characterized by bilateral uveitis frequently associated with neurological (meningeal), auditory, and integumentary symptoms.Auditory manifestations (tinnitus, hearing loss and vertigo) and others (including headache, neck and back stiffness) usually occur before or concurrently with ocular involvement 53 .A previous study linked VKH to SARS-CoV-2 Vaccines 54 .The VKH-like patients in this series responded favorably to corticosteroid therapy.The cases of VKH-like uveitis were particularly notable for their lack of typical systemic symptoms like tinnitus and skin changes, suggesting a unique, non-granulomatous panuveitis potentially triggered by COVID-19.This aligns with observations that COVID-19 may induce a distinct immune or inflammatory pathway, leading to VKH-like manifestations.Both patients showed excellent response to corticosteroid treatment without recurrence, highlighting the effectiveness of standard anti-inflammatory treatments in these atypical presentations.MWDES is related to colds and viral infections.Both patients in this study developed symptoms five days after experiencing SARS-CoV-2-related fever, which is considered a cause.

Rhino-orbital-cerebral mucormycosis (ROCM)
ROCM can be a serious complication of severe SARS-CoV-2 infection, particularly in patients with uncontrolled diabetes.The risk factors predisposing patients to ROCM are uncontrolled diabetes, neutropenia, hematological malignancies, organ transplantation, trauma and burn, and use of immunosuppressants such as corticosteroids 38,39 .Patients were often blinded by mucormycosis invasion of the orbital apex leading to orbital apex syndrome forming retinal artery obstruction.This disease is easily misdiagnosed due to its reputation as a difficult-to-treat mold infection and its high mortality in patients with SARS-CoV-2 infection, particularly those with pulmonary disease.A careful management plan can be successful for rhino-orbital cerebral disease if there is early diagnosis of infection and control of infection 55 .

Table 2.
Retinal and choroidal manifestations in patients after SARS-CoV-2 infection.

Figure 3 .
Figure 3. Multimodal fundus images of an 11 year-old female with AMN.Micro VF and fundus photos (A), mf ERG (B1, B2), IR images (C) and en face images analyzed based on SS-OCTA and SS-OCT B-scan images (D).The BCVAs of her right and left eyes were 0.80 and 0.70 LogMAR.The area enclosed by the yellow line shows the extent of the lesion.The dark area on the en face image (D) was consistent with the range of ellipsoid loss in the B-scan (green dashed line), which was smaller than those areas on Micro VF, mf ERG and IR images.

Figure 4 .
Figure 4. Multimodal fundus images from a 49-year-old female (A, B, C, D, E) and a 43 year-old female (F, G).Initially, the vitreous was opaque in the 49-year-old female (A).FFA (B) and ICGA (C) showed optic disc leakage and fluorescence accumulation in the advanced macula.After 3 days of treatment, the vitreous opacity was reduced (D), and neurosensory retinal detachment decreased (E).In the 43 year-old female, FFA (F) initially showed optic disc leakage.After treatment, neurosensory retinal detachment decreased, and choroidal thickness was reduced over time (G).

Figure 5 .
Figure 5. Multimodal fundus images from a 21 year-old maleFundus photos (A), FAF (B), OCT (C), mf ERG (D), and FFA (E).The area enclosed by the yellow line and indicated by a yellow arrowhead in A2 shows the extent of the lesion.The range of ellipsoid loss in C2 was shown (yellow arrow).

Figure 6 .
Figure 6.Multimodal fundus images from a 49 year-old male patient (A, B, C, D) and a 49-year-old female patient(E, F). White arrowhead showed the cherry erythema in B1, while yellow arrowhead showed the cottonwool spots in B3 where the nerve fiber layer was swelling (C3).F1 showed the acute phase of arterial occlusion with extensive retinal edema.